The present invention relates to a device for use with a display and more particularly, but not exclusively, to light pen systems which interact with a computer display.
A great variety of interactive computer systems and computer input devices useful therewith are known in the art. Various types of light pens are described in the following U.S. Patents, which are believed to represent the current state of the art:
U.S. Pat. Nos. 5,691,749; 5,600,348; 5,187,467; 5,179,368; 5,151,688; 5,138,304; 5,134,389; 4,923,401; 4,812,828; 4,802,722; 4,789,836; 4,771,276; 4,697,175; 4,677,428; 4,675,665; 4,642,459; 4,620,107; 4,602,907; 4,565,947; 4,454,417; 4,377,810; 4,367,465; 4,277,783; 4,263,592; 4,190,831; 4,146,880; 4,129,858; 4,109,146; 4,053,765; 4.017,680; 3,997,891; 3,944,988; 3,758,717; 3,659,281; 3,651,509; 3,594,608; 3,551,896; 3,543,240; 3,506,875; 3,505,561.
The present invention seeks to provide a computer input device which has various advantages over the prior art.
There is thus provided in accordance with a preferred embodiment of the present invention a device for use with a raster display having associated therewith electromagnetic noise which includes signals related to at least one raster synchronization signal, the device including:
an electromagnetic radiation pick up device operative to receive the electromagnetic noise in a wireless manner;
a filter receiving an output from the electromagnetic radiation pick up derive for producing a reconstructed horizontal raster synchronization signal from the electromagnetic noise; and
a correlator correlating an information signal with the horizontal raster synchronization signal received via the filter and the pick up device and with an estimated vertical synchronization signal.
The electromagnetic radiation pick up device is preferably operative to pick up electronic noise generated at the raster display or at an input thereto. It may, for example, be an inductive coil.
The electromagnetic radiation pick up device may alternatively be operative to pick up electronic noise generated at a display signal generator generating an input signal to the raster display. The device may also comprise an information signal generator operative to generate the information signal. The information signal generator may comprise a light receiver which receives light from a region on the raster display and produces an information signal responsive thereto.
According to a second aspect of the invention there is provided a device for use with a display having associated therewith electromagnetic noise which includes signals related to at least one synchronization signal, the device including:
an electromagnetic radiation pick up device operative to receive the electromagnetic noise in a wireless manner;
a filter receiving an output from the electromagnetic radiation pick up device for producing a reconstructed horizontal synchronization signal from the electromagnetic noise; and
a correlator correlating an information signal with the horizontal synchronization signal received via the filter and the pick up device and with an estimated vertical synchronization signal.
The light receiver may produce an information signal indicative of the position thereof relative to the display in three dimensions.
In accordance with a second aspect of the present invention there is provided a device for use with a display having associated therewith electromagnetic noise which includes signals related to at least one synchronization signal, said device including:
an electromagnetic radiation pick up device operative to receive said electromagnetic noise in a wireless manner;
a filter receiving an output from said electromagnetic radiation pick up device for producing a reconstructed horizontal synchronization signal from said electromagnetic noise; and
a correlator correlating an information signal with said at least one reconstructed synchronization signal.
In an embodiment, the electromagnetic radiation pick up device is operative to pick up electronic noise generated at the display.
Alternatively, the electromagnetic radiation pick up device is operative to pick up electromagnetic noise generated by an input to the display.
In a preferred embodiment, the electromagnetic radiation pick up device is operative to pick up electromagnetic noise generated at a display signal generator generating an input signal to the display.
Preferably, an information signal generator is operative to generate the information signal.
The information signal generator comprises a light receiver which receives light from a region on the display and produces an information signal responsive thereto.
In an embodiment, the light receiver produces an information signal indicative of the position thereof relative to a display in three dimensions.
The information signal generator may comprise two or more light receivers, each of which receives light from a different region on the display, and may produce and information signal responsive thereto, the information signal being employed by the correlator for providing information regarding the orientations of two light receivers to said display.
Alternatively, the information signal generator comprises three or more three light receivers, each of which receives light from a different region on the display, and produces an information signal responsive thereto, the information signal being employed by the correlator for providing information regarding the orientations of the light receivers relative to the display.